This is What 400ppm Looks Like: CO2 Levels Highest in More Than 800,000 Years

On Friday, scientists at Scripps Institution of Oceanography, at the University of California, San Diego, recorded CO2 levels higher than the world has seen in over 800,000 years.

From atop the Mauna Loa volcano on the big island of Hawaii—the oldest continuous carbon dioxide measurement station in the world—a reading of just over 400 parts per million (ppm) was recorded this Friday. A similar measurement was made at the National Ocean and Atmospheric Administration (NOAA) station, also in Hawaii. This reading pushes us well past the 350 ppm target scientists say we should stay below if a global temperature rise of 2 degrees Celsius is to be avoided.

This interactive infographic, originally published on The Guardian, gives a more detailed account of just what 400ppm looks like and how these measurements compare to our historic average:

Dr. Charles David Keeling of Scripps began measuring emissions in 1958.

A constant record of CO2 levels has been kept since Keeling developed the now standard ‘Keeling Curve.' It is the most accurate method of measuring carbon dioxide in the air to date and there are several global stations using it to keep an eye on rising emissions. The earliest measurements recorded 310 ppm in the late 1950’s and the global average before the 19th century's Industrial Revolution was 280 ppm.

According to James Butler of NOAA’s Earth System Research Laboratory, a CO2 reading of 400 ppm “[is] mainly important as a milestone that marks a steady progress of increasing carbon dioxide in the atmosphere.”

Marking such progress has been crucial in understanding the global rise of CO2 concentrations and demonstrating the need for improved environmental practices on an international level.

By studying the bubbles trapped in glacier ice, scientists have deduced that the atmosphere hasn’t had this much carbon dioxide in it for 800,000 to 5 million years.

The numbers will dip somewhat when the Northern Hemisphere reaches the height of summer and the leafy forests drink up some of the CO2 in the air. However, according to NOAA, once emitted, the extra “CO2 in the atmosphere and oceans remains for thousands of years.”

This news has hit many scientists hard. Maureen E. Raymo from the Lamont-Doherty Earth Observatory at Columbia University told the New York Times, “It feels like the inevitable march toward disaster.”

Dr. Keeling’s son, Ralph Keeling took over the research at Scripps after his father’s death in 2005. He fears that the levels could reach 450 ppm in the next 25 years if nothing is done to reduce emissions.

Many major contributors to global carbon emissions – like the United States, China and Canada – have no binding national targets and no immediate plans to make them. Without clear guidelines in place, limiting the warming and extreme weather events associated with increased carbon in the atmosphere will be difficult, and likely expensive.

“There’s no stopping the CO2 from reaching 400 ppm,” Ralph Keeling says. “That’s now a done deal. But what happens from here on still matters to climate, and it’s still under our control. It mainly comes down to how much we rely on fossil fuels for energy.”

Infographic Credit:@theduncanclark / The Guardian / Kiln